libguestd/README.md
2024-07-07 18:51:49 +02:00

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# Libguestd
This is supposed to be a library that helps with operations on qemu-guest-agent.
You need to connect to libvirt daemon on your own.
This library implements some(most?) functions described in [QEMU Guest Agent Protocol Reference](https://qemu-project.gitlab.io/qemu/interop/qemu-ga-ref.html).
Not implemented:
- guest-sync-delimited (my understanding is that libvirt does this for me)
- guest-sync (same as above)
- guest-set-time
- guest-shutdown (there is a libvirt command for that already)
- guest-shutdown (there is a libvirt command for that already)
- guest-file-seek (this library only reads/writes whole file)
- guest-file-flush (this library only writes whole file, then closes it immediately)
- guest-fsfreeze-* (there are libvirt commands for that)
- guest-fstrim (I don't need this)
- guest-suspend-*
- guest-get-vcpus (I don't need this)
- guest-set-vcpus (I don't need this)
- guest-get-memory-blocks
- guest-get-memory-block-info
- guest-set-memory-blocks
- guest-get-users (I don't think this is usefull)
- guest-get-timezone
- guest-get-devices (windows only)
Not implemented but I want to implement it:
- guest-get-cpustats
# CLI tools
Alongside this library, a few tools are provided:
## cp2guest
Allows copying files from/to guest using qemu guest agent.
Example usage:
```shell
./bin/cp2guest -domain guesttools -src README.md -dst /tmp/README.md
```
Or, to copy from VM to host:
```shell
./bin/cp2guest -domain guesttools -src /root/anaconda-ks.cfg -dst /tmp/anaconda-ks.cfg -reverse
```
## guestrun
Execute command in guest
Example usage:
```shell
./bin/guestrun -domain guesttools -cmd 'ls -ltrh /bin/'
```
Command will be executed as `/bin/sh -c 'ls -ltrh /bin'`.
## Libguestd-cli
This tool implements most functions of this library.
Since usage should be self-explainatory, I will just leave a few example commands here:
```shell
./bin/libguestd-cli -domain guesttools -username root -password 12345
./bin/libguestd-cli -domain guesttools -username root -sshkey-add 'ssh-ed25519 AAAAC3NzaC1lZDI1NTE5AAAAID8qp7UQUINxLXog/sFgRKDtddiJHzkypyB7/OlmUbK2 lmoskala'\
./bin/libguestd-cli -domain guesttools -username root -sshkey-remove 'ssh-ed25519 AAAAC3NzaC1lZDI1NTE5AAAAID8qp7UQUINxLXog/sFgRKDtddiJHzkypyB7/OlmUbK2 lmoskala'
./bin/libguestd-cli -domain guesttools -username root -listkeys
./bin/libguestd-cli -domain guesttools -username root -fsinfo
```
# Security
Some distributions (rocky linux for example) disables some functionalities of qemu-guest-agent by default.
Most notably, all operations involving files and commands.
Also, selinux is known to cause problems when manipulating SSH keys: [bug report](https://bugzilla.redhat.com/show_bug.cgi?id=1917024)